Stringer having bonded coupling element

ABSTRACT

A stringer for an &#39;&#39;&#39;&#39;invisible&#39;&#39;&#39;&#39; or concealed slide fastener has a pair of stringer halves each comprising a support tape with a doubled-over edge flap to which is bonded an elongated coupling element formed by a series of coupling members. Each element is bonded to the edge flap right up to the edge fold and to this end is formed with a planar surface containing the edge flap. Each member comprises a coupling head of sufficient thickness to ensure a good grip with the opposing members, and a much thinner connecting piece which connects its respective head with the neighboring head to make the fastener flexible.

United States Patent 1191 Hansen 1 June 5, 1973 [54] STRINGER HAVING BONDED 3,141,217 7/1964 Jones ..24 205.13 1) COUPLING ELEMENT 3,430,304 3/1969 Swainson.... ..24 205.1 c [75] Inventor: Harry Ha sen, 2500 xopenhagem 3,484,906 12/1969 Yoshlda ..24/205.l C

y. Denmark FOREIGN PATENTS OR APPLICATIONS 1 1 Assignw Lysta I Kopenhagewvalby, 255,023 7/1963 Australia .424 20513 1) Denmark 1,453,103 8/1966 France ..24/205.1 c [22] Filed: Feb. 10, 1971 Primary ExaminerBernard A. Gelak pp 114,331 Attorney-Karl F. Ross [30] Foreign Application Priority Data ABSTRACT Feb. 14,1970 Germany ..1 20 06 823.9 A Stringer for an invisible concealed Slide fastener has a pair of stringer halves each comprising a [52] U.S. Cl ..24/205.1, 24/205.13 D pp p with a dro g p to which is [51] Int. Cl. ..A44b 19/14, A44b 19/32 bonded an elongated coupling element formed by a [58] Field'ot Search ..24/205-.13 D, 205.1 C, series of coupling members. Each element is bonded 24/205.12, 205.1 to the edge flap right up to the edge fold and to this end is formed with a planar surface containing the [56] References Cited edge flap. Each member comprises a coupling head of sufficient thickness to ensure a good grip with the op- UNITED STATES PATENTS posing members, and a much thinner connecting piece 3,541,649 11/1970 Sim .f. ..24/205.1 C which connects its respective head with the neighbor- 3,517,422 6/1970 Uhrig. ..24/205.1 C ing head to make the fastenerflexible.

2,035,675 3/1936 Sipe ..24/205.l3 D 1 2,066,060 Sipe ..24/ 205.13 D 5 Claims, 4 Drawing Figures PATENTEDJUH 5 I975 HARRY HANSEN l N VEN TOR.

BY 94ml 31055 ATTORNEY STRINGER HAVING BONDED COUPLING ELEMENT FIELD OF THE INVENTION The present invention relates to a slide-fastener stringer usable in an invisible slide fastener. More particularly this invention concerns a slide-fastener stringer whose stringer halves each comprise a support tape with a doubled-over edge flap to which is attached an elongated coupling element.

BACKGROUND OF THE INVENTION ments, the fold line unfolds and the elements are-exv posed. This, of course, is not the effect sought, since the whole idea in invisible or concealed slide fasteners is that, when closed, the two fold lines abut and completely cover the elements. p

The elements are continuous and can be of the coil or meander type, or formed by a series of coupling members. Injection molding or simple extrusion processes can be used to form them of synthetic-resin'material. The coil-and meander-type fasteners, which are made of a synthetic resin monofilament, have excellent flexibility while the type formed simply of a series of block-like teeth or coupling heads joined together by unitary webs is often much less flexible,.even though it usually forms a tighter seal. These elements are usually attached to the tapes by stitching of the chain-stitch or step-stitch type. Adhesive bonding has been found to be applicable to the noninvisible type of slide fastener, but to date its use for invisible slide fasteners has been considered impractical.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an SUMMARY OF THE INVENTION The above objects are obtained according to the present invention by a slide-fastener stringer having halves each comprising a support tape with a doubledover edge flap forming an edge fold, an elongated coupling disposed on the flap and having a row of coupling members each provided with a coupling head overhanging the edge fold, and means for attachingsaid element to the edge flap substantially at the edge fold. The coupling heads project beyond the edge flap by a distance which is a minor fraction of the width of the flap and the transverse width of the coupling elements and which is less than the extent to which each head is received in the interstice between the heads of the opposite coupling element in a mating condition of the stringers.

According to another feature of the present invention this means is an adhesive bond at the interface be tween the edge flap and the coupling element which, in accordance with another feature of this invention, has a planar or flat surface engaging and resting flatly upon the flap.

A stringer so made cannot be flattened out at its fold line, since this fold line is in part defined by the line of attachment between the coupling element and the flap. Thus, a transverse pull across the finished fastener will be transmitted by the tapes directly to the coupling elements, it being impossible to unfold these tapes at the fold line and expose the elements.

It is another feature of the present invention that each coupling member is extruded or injection-molded and includes a connecting piece attaching it to the neighboring coupling member. This connecting piece is substantially narrower (i.e., of lesser transverse width) and is thinner than the coupling head partof the member, so that the element formed thereby has excellent flexibility. The edge folds of the tapes are designed to abut in the mating condition of the coupling elements of the stringer halves, therebyconcealing the fastener when viewed from the side of the tapes opposite that along which the coupling elements are applied.

DESCRIPTION OF THE DRAWING The above and other objects, features, and advantages of the invention will become apparent from the following description, reference being made to the accompanying drawing, in which:

FIG. 1 is a top view of a stringer according to the present invention;

FIG. 2 is a section taken along line ll II of FIG. 1;

FIG. 3 is an enlarged view of the detail of FIG. 2 shown by arrows III; and

FIG. 4 is a section through a different embodiment of the present invention and corresponding toa section taken along line IV IV of FIG. 1. 1

SPECIFIC DESCRIPTION As seen in FIGS. 1 and 2 a slide-fastener stringer has a pair of support tapes 2 each doubled over at l to have an edge flap 6which lies against the tape 2. Each flap 6 carries a unitarilymolded lobar coupling element 3 formed by a plurality of coupling members each in turn formed by a coupling head 4 mounted on a neck 4a connected to a body 4b by a transition region 40 and a connecting piece 5. The underside of the bodies 41;, transition regions4c and connecting webs 5 of each coupling element are flat and coplanar.

Each coupling head 4 is formed by two'mutually axially offset unitary synthetic-resin disks 4' and 4" (FIG. 4) which overhang the fold line 1 and firmly interlock, as shown for the closed fastener in FIG. 1. The neck 40 is of reduced axial width while the body 4b is of an axial width equal to that of the overall axial width of the head 4. The head 4, neck 4a, transition region 4c, and

' body 4b are of like thickness T, as shown in FIG. 3. The

narrow connecting pieces or webs 5 are of the same axial width as the members 4 4c, but have a thickness t equal to about one third of the thickness T of the members they interconnect. This imparts great flexibility to the elements 3, while'making them hold together well. r

The heads 4 overhang the fold line 1 by a distance at most almost equal to and, preferably, less than the depth of interengagement of the two series of heads, so that in an interleaved condition the two fold lines 1 abut and completely hide the elements 3.

The stringer shown in FIGS. 1 3 is made by adhesively bonding the elements 3 to tapes 2 at 7. Application of heat and pressure can be used to make this adhesive bond 7.

In FIG. 4 the element 3, which is thermoplastic, is shown to be welded to the tape flap 6 so that its planar bottom surface even impermeates the flap at 7 or is in part penetrated by the fabric. This can be done by ultrasonic or dielectric welding or the direct application of heat, but here is advantageously carried out by passing the tape, prior to folding at 1, through the head of the injection-molding apparatus which extrudes the elements 3 with the aid of a form band. An adhesive layer may, in addition or alternatively, be applied to the interface 7' and may be of the thermally activatable, vaporizable solvent, or reactive type. Where the fabric is composed in whole or in part of thermoplastic, the coupling element can be heat sealed to the'flap.

Not only is such a bonding much less expensive than sewing, but it allows the entire planar interface between each element 3 and its flap 6 to be interconnected, right up to the fold line. Also, the bonding is effective over the major part of the width of thecoupling element and each body and reaches almost midway of the coupling head which has a flat bottom surface coplanar with that of the body and web. Sewing could not be carried out as close to the fold line.

I claim:

1. A slide-fastener stringer for a slide fastener of the concealed type, comprising a pair of support tapes each having flaps turned about respective fold lines, the fold lines of said tapes being closely juxtaposed; and a pair of molded synthetic resin coupling elements each mounted on the respective tapes, each of said coupling elements comprising a coupling member extending substantially the full thickness of the coupling elements and forming an enlarged head engageable between the heads of the other coupling element, a neck of reduced width in the longitudinal direction of the coupling elements, and a body connected to said neck, each coupling element further comprising webs of the synthetic resin bridging successive bodies, said heads, necks, bodies and webs of each coupling element having a continuous flat surface adhesively bonded to the respective flap at least to the region of said head.

2. The stringer defined in claim 1, wherein said coupling elements are each welded to the respective flap along the respective flat surface.

3. The stringer defined in claim 2, wherein each coupling element is adhesively bonded to the respective flap over its entire flat surface.

4. The stringer defined in claim 3, wherein each of the heads is formed as a pair of offset disk portions.

5. The stringer defined in claim 2, wherein each of said couplingelements is molded onto the respective flap. 

1. A slide-fastener stringer for a slide fastener of the concealed type, comprising a pair of support tapes each having flaps turned about respective fold lines, the fold lines of said tapes being closely juxtaposed; and a pair of molded synthetic resin coupling elements each mounted on the respective tapes, each of said coupling elements comprising a coupling member extending substantially the full thickness of the coupling elements and forming an enlarged head engageable between the heads of the other coupling element, a neck of reduced width in the longitudinal direction of the coupling elements, and a body connected to said neck, each coupling element further comprising webs of the synthetic resin bridging successive bodies, said heads, necks, bodies and webs of each coupling element having a continuous flat surface adhesively bonded to the respective flap at least to the region of said head.
 2. The stringer defined in claim 1, wherein said coupling elements are each welded to the respective flap along the respective flat surface.
 3. The stringer defined in claim 2, wherein each coupling element is adhesively bonded to the respective flap over its entire flat surface.
 4. The stringer defined in claim 3, wherein each of the heads is formed as a pair of offset disk portions.
 5. The stringer defined in claim 2, wherein each of said coupling elements is molded onto the respective flap. 